PHYLUM ARTHROPODA 



319 



TraSc 



mouth (p), with its four triangular lips, regulates the passage of 

 the pollen or honey taken in as food into the true stomach (c.s). 

 The digestive juices se- 

 creted by the walls of the 

 true stomach change the 

 food into chyme. Part 

 of the chyme is absorbed ; 

 the rest of the food ma- 

 terial is forced by mus- 

 cular contractions into 

 the small intestine (si), 

 where digestion and ab- 

 sorption are completed. 

 Undigested particles pass 

 into the rectum (li) and 

 out of the anus. One 

 pair of salivary glands 

 (No. 2) lie in the head, a 

 second pair (No. 3) in the 

 thorax; they pour alka- 

 line secretions upon the 

 food as it is taken into 

 the oesophagus. 



CIRCULATION. -- The 

 blood is a plasma contain- 

 ing ameboid corpuscles, 

 but differs from that 



Of most animals since it u FIG 242. - Respiratory system of worker 

 honey-bee as seen trom above, one anterior 



Carries very little, if any, pair of abdominal sacs removed and transverse 



Oxygen. The dorsal VeS- ventral commissures of abdomen not shown. 



J6 / sp, HI sp, VII sp, spiracles; HtTraSc, Tra 



Sel or heart (Fig. 241, dv) Sc, i, 2, 4, 7, 8, 10, tracheal sacs; Tra, tracheae. 



is the principal organ of <f r ^Tf ?*?' SerieS ' 8> Bur " Ent " 



U. S. Dep t of Agnc.) 



circulation. Blood en- 

 ters it through five pairs of lateral ostia, and is forced forward by 

 rhythmical contractions. From the head region the blood finds 



HtTraSc 



vnsp 



